The present invention is generally directed to a process for purifying and recycling colloidal non-gelatin encapsulation waste materials and derivatives thereof and other components obtained from capsule manufacturing processes.
Gelatin and gelatin derivatives are colloidal materials and are used to encapsulate the products of several industries. Examples are described in U.S. Pat. No. 5,074,102, issued to Simpson et al, and include the encapsulation of medicinal compounds such as drugs and vitamins; employment of gelatin encapsulation in food packaging, such as for powdered instant coffee or spices; in candy manufacturing; in fertilization of ornamental plants and/or indoor plants; in packaging of sensitive seeds in combination with protective agents and/or fertilizers; and in the packing of single dyestuffs or mixtures of various drugs.
Due to market conditions, as discussed below, recent advances allow for encapsulation of the above recited products using materials in the form of colloids which are effective in encapsulating active agents such as drugs, vitamins, neutriceuticals and the like, hereinafter xe2x80x9ccolloidal encapsulating material(s)xe2x80x9d, which do not contain gelatin. Such non-gelatin colloidal encapsulating materials include, for example, 1) starch, starch acetate, high amylase starch, modified starch and derivatives thereof as described in U.S. Pat. No. 5,817,323, issued to Hutchinson, et al. and U.S. Pat. No. 5,554,385, issued to Stroud and U.S. Pat. No. 6,210,1009, issued to Laba, et al., 2) kappa and iota-carrageenan and derivatives thereof as described in U.S. Pat. No. 6,214,376, issued to Gennadios and European Patent No. EP1106107, issued to Tanner, et al. and International Publication No. WO 01/03677 A1, issued to Tanner, et al., 3) cellulose, hydroxypropylmethylcellusle (HPMC) and derivatives thereof as described in U.S. Pat. No. 6,238,696, issued to Wang and UK Patent Application No. 9925166.2, issued to Brown et al. and 4) acacia gum as described in U.S. Pat. No. 6,193,999, issued to Gennadios, or combinations thereof or in combination with gelatin. Each of the references mentioned above is incorporated herein by reference.
The replacement of gelatin by compositions derived from non-animal sources is driven by market conditions that have capsule manufacturers looking toward alternative materials that can effectively encapsulate the various products mentioned above. Some of these market conditions include: 1) the outbreak of BSE (bovine spongiform encephalopathy), or xe2x80x98mad cow diseasexe2x80x99, which has resulted in government action and consumer concerns, tightening raw material supplies as more and more portions of the source material, cow bone and hide, are being banned from use; gelatin products having already been banned in France. There has been one allegation of cross-species contamination from cow to human in the United Kingdom. 2) Foot and Mouth disease outbreak in 2001 resulted in consumer concerns and reduced animal derived raw material supplies. 3) Various groups around the world that do not ingest products of pigs or beef, such as Hebrews, Muslims, Hindus and vegetarians. As raw material supplies become short and government action and consumer concerns expand, non-gelatin colloidal materials will become the preferred sources of encapsulating materials.
In addition, it may be desirable that, an encapsulated product intended for oral use, have a faster disintegration rate, to release the encapsulated product in the oral cavity. Gelatin based colloidal encapsulating materials typically have a relatively slow rate of disintegration compared to non-gelatin colloidal materials.
In each of the above-recited manufacturing and production processes, a certain amount of the encapsulating material is lost as waste. Frequently, the amount lost as waste approaches 40% or more of the total starting material, depending on the manner in which is the capsules are produced. As a result, capsule manufacturers are interested in improving production efficiency by purifying and recycling the waste for reuse.
Methods exist for the recovery and purification of waste material obtained from capsule manufacturing processes which use gelatin based colloidal encapsulating materials. Such methods suffer from a variety of shortcomings as discussed herein. However, there are no known processes for the purification and recovery of non-gelatin colloidal encapsulating materials from capsule manufacturing processes.
Before the shortcomings of waste recovery of gelatin from encapsulating materials employing the same can be fully appreciated, the composition of the encapsulation waste material itself should be further understood. In general, the waste material of encapsulation processes is comprised of a variable number of components added to a base. These components may include solvents (usually water); softening agents and oil coatings; and, contaminants in the form of residual active ingredients, i.e. the substance being encapsulated. In addition, colorings and preservatives may also be present. Thus, it can be observed that the successful recovery and recycling of the purified gelatin involves not only the recovery of the gelatin from surrounding oils, but also the removal of the remaining components of the waste as described above in order to achieve a relatively pure, reusable product.
Under typical waste recovery processes employing gelatin, extraction is the principle method for accomplishing removal of oils, actives, and the like in the pharmaceutical industry. While several solvents have been used in an effort to accomplish separation, each solvent suffer from a variety of shortcomings not the least of which is the necessity of ultimately removing yet another component, i.e. the solvent itself, from the waste material. To date, the most popular and widely used solvents used to separate gelatin from oils and actives are chlorinated solvents such as, for example, 1,1,1,-trichloroethane with naphtha. The use of chlorinated solvents, however, is accompanied by high costs, disposal problems, and most importantly, environmental concerns.
Attempts have been made to use other solvents including isopropyl alcohol, methyl isobutyl ketone, toluene, hexane, heptane, acetone, and acetone/water mixtures, but the resulting yields are insufficient and/or the separation is poor. Furthermore, some of these chemicals are relatively expensive and present similar environmental, disposal, and safety concerns as the chlorinated solvents. None of them have been found to separate oils and actives with a high degree of efficiency. These methods also do not address the intrinsic problem of oils trapped between the ribbons of the waste material that emerge from the encapsulation process.
U.S. Pat. No. 5,288,408, issued to Schmidt et al, discloses a method of recycling gelatin-based encapsulation waste material, and more specifically, to a process for the recovery and purification of gelatin and softening agents from the waste material. In the preferred embodiment, deionized water, is added to the gelatin waste material thereby forming an aqueous solution of gelatin and glycerin dispersed within the remaining oil and residual active-ingredient components of the waste. Filtration methods are employed under specific conditions to effect separation of the solvent (aqueous) layer from the non-solvent layer. The solvent layer is filtered under elevated temperatures to remove any remaining traces of oil or other contaminants and the filtrate is then charged to a concentration vessel adapted for vacuum distillation. The solvent (water) is thus removed under specific thermal and atmospheric conditions until the desired concentration of gelatin and glycerin is achieved. The limitation of the ""408 Patent is that the recovery process described therein is confined to the processing relatively clean gelatin waste streams. The ""408 Patent does not address gelatin waste materials which may contain contaminants residing in the solvent layer containing the gelatin to be recycled, that are miscible with the solvent.
U.S. Pat. No. 5,945,001, issued to Schmidt, provides an advance in the art over Schmidt, et al. (U.S. Pat. No. 5,288,408). The ""001 Patent discloses a method of recycling gelatin-based encapsulation waste material, and more specifically, to a process for the recovery and purification of gelatin and softening agents therefrom. In the preferred embodiment, deionized water is added to the gelatin waste material thereby forming a solution of gelatin and glycerin dispersed within the remaining oil and residual active-ingredient components of the gelatin waste material. Filtration methods are employed under specific conditions to effect separation of the solvent (aqueous) layer from the non-solvent layer. The solvent layer is filtered under elevated temperatures to remove any remaining traces of oil or other contaminants and the filtrate is then subjected to diafiltration rather than vacuum distillation. The Schmidt ""001 Patent is an advance in the art over the Schmidt et al. ""408 Patent in that: 1) a more economical method of solvent removal is employed, 2) water soluble contaminants can now be removed, and 3) low molecular weight degradation products, the result of normal gelatin processing and the recovery process, can be removed. Nonetheless, both the ""001 Patent and the ""408 Patent are limited to a recovery process concerning relatively clean gelatin waste streams; (e.g. neither Patent addresses the removal of waste contaminants from the solvent layer, which are miscible with the solvent layer).
The ""408 Patent and the ""001 Patent while disclosing significant advances and a new approach to purification encapsulation waste streams to obtain recyclable components, nonetheless, had limited ability to remove some contaminants that may be present in some encapsulation waste streams.
It would be a further advance in the art of purifying and recycling waste if an in situ process could be developed that is especially effective in recovering and purifying colloidal encapsulation waste materials containing suspended particles, i.e., emulsified oil droplets or suspended particles, without thermal degradation, in a cost efficient and effective manner, especially waste streams containing non-gelatin colloidal encapsulation waste materials.
The present invention is generally directed to the purification and recovery of non-gelatin colloidal materials from a waste stream derived from capsuled manufacturing processes employing non-gelatin colloid materials as the encapsulating material. The waste stream in addition to the non-gelatin colloid material includes other components which are separated from the waste stream into solvent and non-solvent layers of which the solvent layer is then further treated in accordance with the present invention.
In one aspect of the present invention there is provided a method of treating a non-gelatin colloidal encapsulation waste material to recover non-gelatin colloidal material therefrom comprising:
a) forming a liquid containing the non-gelatin colloidal material; and
b) removing contaminants from the liquid to form a product containing the non-gelatin colloidal material having a higher purity than the non-gelatin colloidal material contained in the liquid formed in step (a).
In a preferred form of the invention, step (a) comprises combining the non-gelatin colloidal encapsulating waste material with a solvent and separating the solvent layer containing the non-gelatin colloidal material from the non-solvent layer and removing contaminants from the solvent layer.